Rock Creek is a stream off the Potomac River that spans 33 miles through Montgomery County, MD, and Washington, D.C. The creek originates from a culvert in Laytonsville, MD, and eventually empties into the Tidewater Lock of the Potomac River in DC. Much of Rock Creek is located within Rock Creek Park, which is an oasis of recreation and well-being for residents in both DC and MD.​

Report Highlights and Opportunities for Improvement:

Rock Creek received a Fair score in its overall stream health. As a valued watershed in both DC and MD, much of Rock Creek is located within the Rock Creek Park Corridor, which is a national park in DC and a county park in Montgomery County. With its proximity to urban communities, Rock Creek had high scores in both Tree Equity and Park Access. It also scored well for Stream (Riparian) Buffer, Birds, and Water Chemistry.

Our report also showed opportunities for improvement. Rock Creek’s lowest score was for dams and barriers within the creek. One such dam can be seen at Peirce Mill in Northwest DC. In 1904, people created a dam at Peirce Mill to create a scenic waterfall. Despite its beauty, this dam had a negative impact on the breeding cycle of the Potomac herring, a fish that migrates through Rock Creek to lay its eggs. Fortunately, in 2007, the National Park Service installed a fish ladder that the herring can use to bypass the dam. If you look closely in springtime, you may be able to see herring using the fish ladder at Peirce Mill.

Like many of the streams in this report, Rock Creek has to contend with the pressures of impervious surface from an urbanized environment, invasive plants, and tree canopy. Learn more about Rock Creek and help to improve its health through our partner, Rock Creek Conservancy.